Our knowledge of the emission of radiant energy from various substances at different temperatures is limited. It has been found that the emission spectra of the Bunsen flame and of gases in vacuum tubes are composed of sharp emission bands superposed on a weak continuous spectrum, whereas solids generally emit continuous spectra. The present paper contains the emission spectra of numerous substances of which it has not been practicable to study the absorption spectra. The substances examined were electrical insulators, and were in the form of solid rods made in the oxyhydrogen flame or in the form of thick layers placed upon a heater. They were given an initial heating by means of an electric current from the secondary of a 2,000-volt, 300-watt transformer, a

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